There is only one certainty when Oprah Winfrey's interview with Lance Armstrong is beamed across the world next week. It is that it cannot possibly provoke even a wisp of the anguished doubt that, according to fable, went into the cry of a Chicago street kid when another fallen American hero, 'Shoeless' Joe Jackson, was arraigned in the Black Sox World Series baseball scandal 94 years ago.
"Say it ain't so, Joe," the boy was said to have shouted.
The difference now is that we know that Armstrong is guilty. We know the evidence is as heavy as any avalanche in the Pyrenees where he worked and controlled arguably the greatest deceit sport has ever known.
This does not mean, however, that anyone who cares about the future not just of cycling, but of all high-level competitive sport, can afford to miss the Oprah interview.
When the Olympic "superwoman" Marion Jones appeared on the show after doing time for perjury in the wake of her conviction for using performance-enhancing drugs, she put in an act of such self-serving evasions that it didn't so much clear the air as further poison some extremely stagnant water. Armstrong will be making his final, self-destroying mistake if he even flirts with such a manoeuvre.
As the man who once owned seven Tour de France titles, who convinced millions that if you worked hard enough and had sufficient courage, you could reach every peak – and on the way lick cancer – the 41-year-old Texan is shorn of everything he worked for. Now, he has one last solemn duty to his family, to those of his followers who remain loyal to the legend fuelled by so many lies, to his sport and, most of all, to himself. He has the huge, if ultimately lonely, capacity not only to explain his own actions, but also every nuance of the sports culture he deemed it necessary to subvert.
A prevailing theory is that Armstrong is finally prepared to tear down the curtain of denial behind which he created a monstrous success. The motivation is plain enough. He has lost everything that he amassed so cynically and so ruthlessly, and now he has one last plea bargain.
It is to exchange the most forensic examination of his extraordinary journey to power and success and his relentless shaping of the morality of almost every rider who shared his colours, with the chance to draw some kind of line between the unremitting lies of his past and the possibility of some kind of different future.
His confession has to be purged of any colour but black and white. There are no grey areas left for the man who only this week was accused by the head of Usada (the American anti-doping agency) of offering them a "donation" of £150,000 "sometime after 2004" – when suspicion of Armstrong was gathering force. "I was stunned," said Travis Tygart.
"It was a clear conflict of interest for Usada and we had no hesitation in rejecting that offer."
Armstrong can talk about his relations with the ruling authority of cycling, the UCI, whose president Pat McQuaid categorised whistle-blowers Floyd Landis and Tyler Hamilton as "scumbags" and accepted, on behalf of the UCI, a $100,000 donation from the man who was so masterfully manipulating the great events under its supervision.
We need to know from Armstrong's own lips the workings of his supply lines. Was it really true that he casually directed a fellow rider at his home to the fridge where supplies of EPO were lined up in neat little packages? Did he really play god with the careers of riders who might just, on their own, have elected to ride clean?
Maybe he will insist that such innocents are a figment of somebody's imagination. He might say that everyone knew there was only one way, at least in the climate of the sport at that time, to win the great prizes and that any other version of reality is still another blurring of the issue.
Many years ago, the great Jacques Anquetil, who won the Tour de France five times in eight years, said that the wonder to him was not that the "boys" took chemical assistance, but that anyone imagined they could complete such a physically draining course without a helping hand. The implication was plain enough: if, for reasons of spectacle and commercial exploitation, you make inhuman demands, then do not be surprised by the inevitable consequences.
We can only hope that Armstrong has, indeed, been flushed, utterly, from the foxhole of his denial. It is, he may have grasped, a little late for the evasions and the self-pity of a Marion Jones.
Of course, there is small potential for the old heroism in the wide-open confessional box of Oprah Winfrey. But there is one last opportunity for him to display some of that courage which so many believed was the most basic strength of his character.
He can do the best thing he has ever done. He can tell the truth.